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Potential Energy and Conservation of Energy, image, Screenshot (20), Low…
Potential Energy and Conservation of Energy
Conservative and Nonconservative Forces
Conservative forces
work done depends only on the initial and final positions, independent of the path taken
net work done by the force on an object moving around any closed path is zero
Eg: Gravitaional, elastic, electrical
Nonconservative forces
work done depends not only on the initial point and ending point, but also the path taken.
Eg: friction, air resistance, tension in cord
Potential Energy
is a property of a system as a whole, not just of the object but also depends on external forces
U = mgy
F = -kx
Mechanical Energy and Its Conservation
if no nonconservative forces, sum of change in kinetic energy and in the potential energy is zero and E=K + U
The principle of conservation of mechanical energy states that if only conservative forces are doing work, the total mechanical energy of a system neither increases nor decreases in any process. It stays constant-it is conserved
Problem Solving Using Conservation of Mechanical Energy
The Law of Conservation of Energy
Nonconservative forces do not conserve mechanical energy
K + U + change in other forms of energy = 0
Gravitational Potential Energy and Escape Velocity
Power
Unit = watts(W)
1hp = 746W
P = Fv
Potential Energy Diagram
Low Jing Ning A20SC0126
